The long term goals of the research program are to understand and explain on a molecular and biochemical level the structure function relationship of collagenous connective tissues which provide the support for the body. The collagen that supplies the major portion of the support of the body and many of the organs is genetic type 1 collagen. This proposal deals with the mechanisms involved in stabilizing collagen molecules in the fibrillar matrices. From these studies we can obtain answers to fundamental questions concerning the three dimensional structure of collagen and its very varied functional role in an organism. The solution will aid us greatly in understanding the biology of collagen and its task in the multivarient tissues of the body. By solving the three dimensional structure of collagen and defining the stabilizing forces of the matrices we shall begin to understand the stress and strains that matrices in withstand. This is particularly important in sports medicine and other branches of health related sciences where collagen matrices play a significant role as a connective tissue. We will be using native insoluble as well as reconstituted collagen fibrils that will and will not be subjected to incubation techniques to study the mechanism of cross-linking reactions. These studies will result in determining the stereochemistry of collagen molecules disposed on a hexagonal lattice and the stereospecificity involved when molecules are assembled into fibrils in vivo since fibril formation occurs before cross-link formation. Quantitative molecular location of NaBH4-reduced cross-link peptides will enable us to determine the ratio of cross-linked alpha1(I) to cross-linked alpha2(I) chains of collagen molecules in fibrils. By understanding the organic chemical mechanisms of the manner in which the cross- links form, we shall be able to calculate from the transition states of reaction,the conformations of the molecules when cross- linking takes place. Finally we shall be investigating the function of the glycosylation of specific Hyl residues in collagen and their role in stable nonreducible cross-link formation. This will provide insights to whether or not glycosylated cross-links play a role in turn over of collagen in the body.